Filter-press electrolyzer



' July 16,1929. R PECHKRANZ 1121,40?

FILTER PRESS ELECTROLYZER Filed July 10, 1925 wm/mq- Patented July 16, 1929.

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Application filed July 10, 1925, Serial No. 42,860, and. in- Switzerland August 2, 13.24.

The packingof the partitions or of the frame carrying them and-the adjacent electrodes, or the interpacking of the electrodes tl1e1nselves,by means of linings of electrically ,insiilating, compressible or elastic materials is known, particularly in connection with apparatus with several cells for decomposing water. Asbestos and rubber-cord have been much used for this purpose. Also a mixture of mica and rubber have already been proposed.

Experience has shown that none of these packings is durable. The parts of the metal electrodes on which the linings abut are corroded by the damp, which collects in the more or less strongly hygroscopic linings, and, from this alone, leaky places are caused, even if the cords are not dan'iaged by the gases and electrolyte. These leaky places result, however, in great disadvantages, such as for example, loss of gases, current loss, short circuits to the'outside, and impurification of the gases by the neutralizingtendency of the current losses, quite apart from the decomposition of the electrolyte by the carbon dioxide in the air. It is therefore understandable that 1n face of such losses, the experts have been strivmg contlnuously since the commencement of the first water decomposer to find feasible methods and means to make a durable packing. Their efforts have, however, till now, met with no success.

The subject of the invention is a method of making a durable packing for electrolytic apparatus for the decomposition of water, according to which an electrically insulating lining is introduced between the surfaces to be packed against the leakage of gases and electrolyte, or a cover protecting the joints is mounted over the edge surfaces. The invention consists in the utilization of the lining as a carrier for a pasty, semi-liquid or wholly liquid hydrocarbon.

All solid, pasty, semi-liquid and liquid bitumens which are regained by the refining of petroleum or its derivatives, which melt under the influence of heat, which consists of a combination of hydrocarbons and derivatives of hydrocarbons with complex structure, and

which are represented by strongly cyclic, or

bridge formulae, come, into consideration as cmployable hydrocarbons.

As a carrier for the hydrocarbons asbestos may be used, and may, if necessary be made more spongy by a suitable treatment to obtain-a thorough soaking of the fibres by the impregnation. hen a rather pasty or altogether plastic hydrocarbon is used, the carrier employed as a lining may also have a covering limited to. its outer periphery only. Further, any other material of fibrous structuremay be used as a lining and as a carrier for the hydrocarbons, e. g. cotton, hemp and the like. Thereis no limitation however, to a lining of fibrous nature.

A practical application of the process is illustrated in the accompanying drawings, in which Figures 1, 2 and?) areconsecutively sectional views of two cells of an electrolytic apparatus showing several adaptations of my insulating and decomposition-proof packing.

Referring now in detail to the several figures in which similar reference characters are applied to similar parts, 1 shows a portion of a frame for receiving a diaphragm of an electrolytic cell, and 2 is the leakage preventing packing arranged either between (Figs. 1 and 3) or around (Fig. 2) said frames. As above explained the packing 2 is the carrier of a pasty, semi-liquid or liquid hydrocarbon, adapted to durably resist the influence of the gases and the acting as an lnsulation against the electric current.

According to Fig. 1 the string 2 saturated for instance with tar, is inserted between the walls 1 of the frame 1 whereupon these latter are pressed together in the usual way by means of spindle screws.

In the embodiment represented in Fig. 2

a strip-like member 2 saturated for instance with pitch is fitted on the bottom 1 around the joint separating the two adjoining frames. It will easily be understood that the stripmember 2 may be made to adhereto the surface of the frame bottoms in any convenient manner.

According to Fig. 3 an arc-shaped recess 4 is provided for in the adjoining walls of the frames 1, which are filled with a very viscous tar 5 into which the string 6 made from ordinary asbestos fibres is thereupon inserted. The asbestos string may not have been soaked previously with a hydrocarbon whatever since the tar layer 5 will serve to entirely coat the string 6. It is evident, that more than one string 6 may be inserted either into the same recess 4 provided above the single one shown in Fig. 3, or in other recesses 4: arranged towards the interior of the frame. The asbestos cord is impregnated in tar reduced by warming to a good liquid state,

and is, before the tar has attained the final solidity of the cold condition, introduced, if necessary 1n specially provlded grooves,

between the surfaces between which the leak-- age of gases or of the electrolyte is to be prevented.

It is also conceivable that the edge portions of the surfaces, e. of the electrodes of a water decomposing apparatus built like a filter press, may undergo a further and special warming before the tightening of the press spindle, in order to reliquefy the more or less strongly consistent hydrocarbon and thereby to attain a very thorough connection with the metal surfaces.

Further the places on which the lining rests may be coated with a pasty or plastic hydrocarbon, or specially provided grooves are filled therewith, a proportionally thin lining may then be embedded in said coating or in said filling so that the lining is con' pletely surrounded by the hydrocarbon, and becomes accordingly at the same time, the support, at least on its outside surfaces, of the pasty hydrocarbon.

A lining treated in this manner, resists the harmful influences of all common electrolytes, caustic lye, soda lye, even if warm and con centrated, and also solutions containing chlorine, and is not attacked even in the presence of free oxygen. It cannot become porous and has good insulating properties. If the hydrocarbon is judiciously selected the lining may retain its original plia-bility or may regain the same by subjection to a suitable treatment.

Hydrocarbons may naturally be mixed together to get the desired consistency and any other particular properties for the impregnated or coated lining.

The hydrocarbon employed may be allowed to form physical or chemical combinations with other materials such as, for example, emarex, which is a mixture of mineral rub her with sulphur,,chalk litharge or the like.

The conversion at least temporarily of relatively solid hydrocarbons into a pasty, semiliquid, or liquid condition can be effected, for instance, by warming or by the admixture of volatile dissolving agents such as benzol.

I claim:

1. In a filter-press electrolyzcr of the type including a. series of frames adapted to be held in unitary relation by pressure transmitted cndwise through said series, the combination of adjacent metallic frames having an electrically nonconductive, non-hygro scopic and adhesive packing therebetween, said packing being adhesively bonded to the adjacent faces of said frames when the latter are held under said pressure.

2. In a filter-press electrolyzer of the type including a series of frames adapted to be held in unitary relation by pressure transmitted endwise through said series, the combination of adjacent metallic frames having a packing therebetween formed from fibrous asbestos impregnated with a viscous hydrocarbon, said packing being adhesively bonded to the adjacent faces of said frame when the latter are held under said presusre.

In testimony whereof I afiix my signature.

RODOLPHE PECHKRANZ. 

